Hydraulic pump with flow guider

ABSTRACT

“A synchronous hydraulic pump for dishwashers and washing machines comprising a synchronous motor ( 1 ), an impeller ( 2 ) coaxial to said synchronous motor ( 1 ) and a hydraulic body ( 3 ), said impeller ( 2 ) being housed in said hydraulic body ( 3 ) and the hydraulic body ( 3 ) having an inlet pipe ( 4 ) and an outlet pipe ( 5 ). The pump also comprises at least one piece ( 8 ) adjacent to the impeller ( 2 ), said piece ( 8 ) having a projection ( 9 ) pointing at the outlet pipe ( 5 ), in such a way that said projection ( 9 ) acts as a guider directing the flow circulating inside the hydraulic body ( 3 ) towards the outlet pipe ( 5 ).”

TECHNICAL FIELD

[0001] The present invention relates to hydraulic pumps for dishwashersand washing machines, and more specifically to synchronous hydraulicpumps.

BACKGROUND OF THE INVENTION

[0002] Synchronous hydraulic pumps for dishwashers and washing machinesare already known. Said pumps comprise a synchronous motor, an impellercoaxial to said synchronous motor and a hydraulic body, said impellerbeing housed in said hydraulic body. The hydraulic body has an inletpipe and an outlet pipe, the incoming water being evacuated from theformer to the latter pipe by means of the rotation of the impeller.

[0003] Pumps of this type usually have priming problems due to the airthat builds up together with the water inside the hydraulic body. Onesolution so that the least possible amount of air collects inside thehydraulic body is to reduce the space inside said hydraulic body (andtherefore the place where air could be housed) to a minimum. This isoften not feasible due to the hydraulic or dimensional requirements ofthe housing where the pump is installed.

[0004] Another solution is to force out the air that collects inside thehydraulic pump adding a third pipe to the hydraulic body at the top, viawhich the air is evacuated to the exterior, being forced out to thewashing chamber. The existence of said third pipe for air recirculationnevertheless brings about a loss of output flow, a loss that will begreater the larger the diameter of the third pipe is. Therefore, so thatthe flow loss may be as little as possible, small diameters are used inrelation to the diameter of the outlet pipe. This means that, during thelifetime of the appliance, said third pipe becomes blocked and requiresthe intervention of the technical service. In addition, dirty waterrecirculates through said third pipe to the washing chamber, therebyreducing the washing quality of the appliance.

[0005] On the other hand, it is important to increase the output flow ofthe pump as much as possible. One way to do so is to increase theimpeller's dimensions, but this entails higher power consumption alongwith noisier pump operation.

DESCRIPTION OF THE INVENTION

[0006] The main object of the invention is to provide a synchronoushydraulic pump that overcomes the priming problem without the need toincorporate a third pipe for air recirculation.

[0007] The hydraulic pump of the invention comprises a synchronousmotor, an impeller coaxial to said synchronous motor and a hydraulicbody, said impeller being housed in said hydraulic body and thehydraulic body having an inlet pipe and an outlet pipe. Said pump alsocomprises at least one piece adjacent to the impeller which has aprojection pointing towards the outlet pipe, in such a way that saidprojection acts as a guider directing the flow circulating inside thehydraulic body towards said outlet pipe.

[0008] In this way, a good proportion of the mass of water is preventedfrom circulating permanently “integral” with the impeller together withthe accumulated air. Thus, the air that would otherwise build up insidethe hydraulic body is forced out via the outlet pipe, along with themass of water, so that the priming problem is resolved. Furthermore,besides overcoming the priming problem, directing the flow alsoincreases output delivery considerably.

[0009] Therefore, the invention has the following advantages:

[0010] the priming problem is solved without the use of a third pipe forair recirculation, whereby the drawbacks stemming from the use of thisthird pipe are avoided, and

[0011] a considerable output flow is obtained without having to increasethe dimensions of the impeller, whereby the increased power consumptionthat would be involved is avoided, and also the increased noise levelentailed.

[0012] The piece that acts as a guider directs the flow towards theoutlet pipe irrespective of the direction of rotation of the impeller.

DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of a synchronous hydraulic pump ofthe prior art.

[0014]FIG. 2 is a cross-sectional perspective view of the lower half ofa hydraulic pump according to a first embodiment of the invention.

[0015]FIG. 3 is a cross-sectional plan view of the lower half of thehydraulic pump of the embodiment of FIG. 1.

[0016]FIG. 4 is a cross-sectional perspective view of the upper half ofa hydraulic pump according to a second embodiment of the invention.

[0017]FIG. 5 is a cross-sectional plan view of the upper half of thehydraulic pump of the embodiment of FIG. 4.

DETAILED DISCLOSURE OF THE INVENTION

[0018] The synchronous hydraulic pump of FIG. 1 include a synchronousmotor 1, an impeller 2 (not shown in this FIG. 1) coaxial to saidsynchronous motor 1 and a hydraulic body 3 where the impeller 2 ishoused, said hydraulic body having an inlet pipe 4 and an outlet pipe 5.The impeller 2 rotates in relation to the shaft 6.

[0019] The pump of FIG. 1 includes a third pipe 7 at the top for airrecirculation. It may be observed that the diameter of the third pipe 7is considerably smaller than the diameter of the inlet pipe 4 and theoutlet pipe 5.

[0020] A third pipe is not needed on the pump of the invention.Experimental tests carried out with the hydraulic pump of the inventionhave shown that the output delivery that is obtained with the layout ofthe invention is increased considerably in relation to that obtainedwith the pump of FIG. 1.

[0021] The cross-sectional views of FIGS. 2 and 3 show a firstembodiment of the invention. The sectional plane is perpendicular to theshaft 6 of the impeller 2 and the lower half of the pump is shown, as itis the part of the pump that is modified in this first embodiment.

[0022] In this first embodiment, the pump includes, under the impeller2, a piece 8 provided with a projection 9 pointing towards the outletpipe 5, so that this projection acts as a guider directing the flowcirculating inside the hydraulic pump 3 towards said outlet pipe 5.

[0023] The piece 8 is placed between the impeller 2 and the synchronousmotor 1, attached to said synchronous motor 1. Said piece 8 may also beintegral with the body of the synchronous motor 1. The piece 8 iscoaxial to the impeller 2 and has a substantially cylindrical outline 10all around its outside edge, except at the projection 9, which isformed, as shown in FIG. 3, by two planes 10 a and 10 b tangential tosaid cylindrical outline 10 which extend on towards the outlet pipe 5until both planes intersect. The intersection may be in the form of asharp edge or else have a slight rounded outline.

[0024] As shown in FIG. 3, both plane 10 a and plane 10 b extendapproximately towards the vertex of the outlet pipe 5 farthest away inrelation to the point from where they start.

[0025] The cross-sectional views of FIGS. 4 and 5 show a secondembodiment of the invention. The cross-sectional plane is perpendicularto the shaft 6 of the impeller 2 and shows the upper half of the pump,as it is the part that is modified in this second embodiment.

[0026] In this second embodiment the piece 8 is above the impeller 2 andis integral with the hydraulic body 3. Said piece 8 may also be anindependent piece attached to the hydraulic body 3. It may be observedthat, in all other respects, the characteristics of the piece 8 of thissecond embodiment are the same as the aforesaid piece 8 had in the firstembodiment.

[0027] There is a third embodiment of the invention that combines thefirst two embodiments, in such a way that it includes a first piece 8attached to the synchronous motor 1 and a second piece 8 integral withthe hydraulic body 3. Although in the preferred execution of this thirdembodiment the first piece 8 is an independent piece and the secondpiece 8 is integral with the hydraulic body, the first piece 8 may alsobe integral with the body of the synchronous motor 1 and the secondpiece 8 may also be an independent piece.

What is claimed is:
 1. A synchronous hydraulic pump for dishwashers andwashing machines comprising a synchronous motor; an impeller coaxial tosaid synchronous motor; a hydraulic body, said impeller being housed insaid hydraulic body and the hydraulic body having an inlet pipe and anoutlet pipe; and at least one piece adjacent to the impeller which has aprojection pointing towards the outlet pipe, wherein said projectionacts as a guider directing the flow circulating inside the hydraulicbody towards said outlet pipe.
 2. A synchronous hydraulic pump accordingto claim 1, wherein said piece is coaxial to the impeller and has asubstantially cylindrical outline all around its outside edge except atthe projection, which is formed by two planes tangential to saidcylindrical outline, said two planes extending towards the outlet pipeuntil they intersect.
 3. A synchronous hydraulic pump according to claim2, wherein said two planes extend approximately towards the vertex ofthe outlet pipe farthest away in relation to the point where they start.4. A synchronous hydraulic pump according to claim 1, wherein said pieceis placed between the impeller and the synchronous motor, said piecebeing attached to the synchronous motor.
 5. A synchronous hydraulic pumpaccording to claim 4, wherein said piece is an independent piece.
 6. Asynchronous hydraulic pump according to claim 4, wherein said piece isintegral with the synchronous motor.
 7. A synchronous hydraulic pumpaccording to claim 1, wherein the piece is above the impeller and isattached to the hydraulic body.
 8. A synchronous hydraulic pumpaccording to claim 7, wherein said piece is an independent piece.
 9. Asynchronous hydraulic pump according to claim 7, wherein said piece isintegral with the hydraulic body.
 10. A synchronous hydraulic pumpaccording to claim 1, comprising a first piece fitted between theimpeller and the synchronous motor, said first piece being attached tosaid synchronous motor, and a second piece attached to the hydraulicbody.